Alright, Sir! It was indeed the main-user.cfg - file!
Thank you very much @JackDole, you saved my weekend

https://pastebin.com/QtDuUFti
Here it is. Hope, it was right like that

Hello together :) I'm new in here and first of all I want to thank you all for keeping this awesome programme running! SE is a true miracle! :) Now why I am here: I have the standard version on Steam and since 2 days, SE is not launching anymore. I read through the forum and tried the trick with the...